Problem: What is the least common multiple of $12$ and $9$ ? $\text{lcm}(12, 9) = $
Explanation: The least common multiple is the smallest number that is a multiple of $12$ and $9$. We know that $12 \times 9$ (or $108$ ) is a common multiple, but is it the least common multiple? Write out the multiples of $12$ until we find a number divisible by $9$. $12, 24, 36$ So, the least common multiple of $12$ and $9$ is $36$.